WizardLM 13B needs ~23.0 GB VRAM. RTX 4000 Ada 20GB has 20.0 GB. With Q4_K_M quantization, expect ~20 tok/s.
Operating mode
Interactive favors responsiveness, while light API and scale-out lean harder on serving readiness. The fit stays the same, but the recommendation lens changes.
Current mode
Balanced
Balanced for general local use. Keeps the ranking neutral across personal and serving workflows.
Select quantization to explore
3.0 GB over capacity — needs offload or smaller quantization
Fit status
Very compromised (needs ~1 GB host RAM)
Decode
19.7 tok/s
TTFT
9817 ms
Safe context
8K
Memory
23.0 GB / 20.0 GB
Offload
10%
It fits through host-memory offload, and offload is the main reason performance drops.
CPU or host-memory offload is active
About 10% of the working set spills out of accelerator memory, which usually hurts latency and sustained decode throughput.
Very little memory headroom
You can run the model, but there is not much room left for longer context, bigger batches, extra apps, or future model updates.
Remove offload with more accelerator memory
Prioritize a GPU or unified-memory tier that fits the whole model natively. Removing offload usually helps more than small compute gains.
Buy headroom, not only minimum fit
A slightly larger memory tier gives you safer context growth and makes the recommendation more future-proof.
Increase host RAM if you keep offloading
This setup may need roughly 1.0 GB of extra host RAM just for the offloaded portion, before OS and other tools.
| Workload | Grade | Fit | Decode | TTFT | Context |
|---|---|---|---|---|---|
| Chat | A | Tight fit | 35.4 tok/s | 2982 ms | 8K |
| Coding | B | Very compromised (needs ~1 GB host RAM) | 19.7 tok/s | 9817 ms | 8K |
| Agentic Coding | F | Too heavy | 8.1 tok/s | 34946 ms | 8K |
| Reasoning | B | Very compromised (needs ~1 GB host RAM) | 19.7 tok/s | 11601 ms | 8K |
| RAG | F | Too heavy | 8.1 tok/s | 43682 ms | 8K |
Inference speed
Estimated decode speed (tokens/sec) for WizardLM 13B at Q4_K_M across popular GPUs and Apple Silicon, using the fastest local runtime per device. Fastest is RTX 5090 32GB at ~151 tok/s. Speed is memory-bandwidth bound, so cards that fit the whole model in VRAM run far faster than ones that offload to system RAM.
| GPU / Mac | Memory | Quant | Speed (tok/s) | Fits? |
|---|---|---|---|---|
 RTX 5090 32GB | 32 GB | Q4_K_M | 151.4 | Fits |
| RTX 4090 24GB | 24 GB | Q4_K_M | 96.6 | Offloads |
RX 7900 XTX 24GB | 24 GB | Q4_K_M | 87.2 | Offloads |
| RTX 3090 24GB | 24 GB | Q4_K_M | 82.6 | Offloads |
Mac Studio M3 Ultra 256GB | 256 GB | Q4_K_M | 70.2 | Fits |
Mac Studio M2 Ultra 128GB | 128 GB | Q4_K_M | 58.5 | Fits |
Mac Studio M1 Ultra 128GB | 128 GB | Q4_K_M | 55.5 | Fits |
MacBook Pro M4 Max 128GB | 128 GB | Q4_K_M | 38.2 | Fits |
MacBook Pro M4 Max 64GB | 64 GB | Q4_K_M | 38.2 | Fits |
MacBook Pro M3 Max 64GB | 64 GB | Q4_K_M | 30.3 | Fits |
MacBook Pro M1 Max 64GB | 64 GB | Q4_K_M | 27.7 | Fits |
| RTX 4080 Super 16GB | 16 GB | Q4_K_M | 27.1 | Too big |
MacBook Pro M4 Pro 48GB | 48 GB | Q4_K_M | 23.3 | Fits |
| RTX 4070 12GB | 12 GB | Q4_K_M | 9.5 | Too big |
| RTX 3060 12GB | 12 GB | Q4_K_M | 6.0 | Too big |
| RTX 4060 8GB | 8 GB | Q4_K_M | 3.8 | Too big |
Estimates for single-stream decoding at Q4_K_M; real tokens/sec varies with prompt length, context, batch size, and runtime build. Prompt processing (prefill) is faster than the decode figures shown here.
How WizardLM 13B (13B params) fits at each quantization level on RTX 4000 Ada 20GB (20.0 GB usable).
| Quant | Bits | VRAM | Quality | Fit |
|---|---|---|---|---|
Q2_K | 2 | 5.1 GB | Low | B68 |
Q3_K_S | 3 | 6.4 GB | Low | B68 |
NVFP4 | 4 | 7.3 GB | Medium | B69 |
Q4_K_M | 4 | 7.9 GB | Medium | B70 |
Q5_K_M | 5 | 9.4 GB | High | A71 |
Q6_K | 6 | 10.7 GB | High | A71 |
Q8_0Best for your GPU | 8 | 13.9 GB | Very High | A71 |
F16 | 16 | 26.7 GB | Maximum | F0 |
Copy-paste commands to run WizardLM 13B on your machine.
Run
lms load WizardLM-13B-V1.0 && lms server startアップグレードオプション
RTX 3090 24GBコスパ重視Removes host-memory offload, which is usually the single biggest latency and throughput win.
Raises estimated decode speed by about 311%.
〜$1,499 MSRP
RTX 4090 24GBコスパ最良Removes host-memory offload, which is usually the single biggest latency and throughput win.
Raises estimated decode speed by about 415%.
〜$1,599 MSRP
RTX PRO 4000 Blackwell 24GBNVIDIAアップグレードRemoves host-memory offload, which is usually the single biggest latency and throughput win.
Raises estimated decode speed by about 261%.
〜$1,599 MSRP
Yes, RTX 4000 Ada 20GB can run WizardLM 13B with a B grade (Very compromised (needs ~1 GB host RAM)). Expected decode speed: 19.7 tok/s.
WizardLM 13B (13B parameters) requires approximately 23.0 GB of memory with Q4_K_M quantization.
The recommended quantization for WizardLM 13B is Q4_K_M, which balances quality and memory efficiency.
On RTX 4000 Ada 20GB, WizardLM 13B achieves approximately 19.7 tokens per second decode speed with a time-to-first-token of 9817ms using Q4_K_M quantization.
For coding workloads, WizardLM 13B on RTX 4000 Ada 20GB receives a B grade with 19.7 tok/s and 8K context.
On RTX 4000 Ada 20GB, WizardLM 13B can safely use up to 8K tokens of context. The model's official context limit is 8K, but available memory constrains the safe maximum.
Remove offload with more accelerator memory. Prioritize a GPU or unified-memory tier that fits the whole model natively. Removing offload usually helps more than small compute gains.
Paste this snippet into any page to show a live fit card.
<iframe src="https://willitrunai.com/embed/wizardlm-13b-on-rtx-4000-ada-20gb" width="400" height="180" frameborder="0" style="border:none;border-radius:12px;overflow:hidden;" title="Will It Run AI — fit result"></iframe>
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